A lid lock structure of a storing box for a vehicle for preventing a lid of a storing box provided in a vehicle from opening due to impact force produced by a vehicle collision or the like has been known heretofore (for reference, see Japanese Examined Utility Model Publication No. Hei. 5-47234).
FIGS. 1 and 2 illustrate a conventional lid lock structure of a storing box for a vehicle. In FIG. 1, reference numeral 1 denotes an instrument panel, and reference numeral 2 denotes a storing box provided in the instrumental panel 1.
Paired hinge brackets 3 are provided in the respective two sides of an upper part of an opening part of the storing box 2. Two end parts of an upper part of a lid 4 are rotatably attached to these hinge brackets 3. Thus, the lid opens and closes the opening part of the storing box 2.
Paired engagement pin portions 5 are formed in a lower part of the rear of the lid 4. Attachment flanges 6 are formed in two sides of the opening part of the storing box 2.
Paired lock devices 7 are provided in lower parts of the attachment flanges 6, and their provided locations correspond to the engagement pin portions 5. One of the attachment flanges 6 is provided with a restriction device 8 above its lock device 7.
Each lock device 7 has what is termed as a push latch mechanism. When the lid 4 is repeatedly pushed from its front side while the lid 4 is closed, the push latch mechanism causes the lock device 7 to alternately repeat a state of holding the engagement pin portion 5 and a state of releasing the engagement pin portion 5, each time the lid 4 is pushed.
By this push latch mechanism, a locked state of the lid 4 and an unlocked state of the lid 4 are alternately switched, each time the lid 4 is pushed repeatedly.
The concrete structure of the push latch mechanism is based on the art which has been publicly known heretofore. For this reason, further description thereof will be omitted.
The restriction device 8 is configured of a case portion 9, a weight portion 10, a stopper portion 11, and springs 12 and 13.
The weight portion 10 is slidably supported in the vehicle front-rear direction in the case portion 9. The stopper portion 11 is formed above the case portion 9, and is supported movably in ascending-descending directions inside a cylinder portion extending in the directions which the lid 4 opens and closes.
The spring 12 is fitted onto the front end part of the weight portion 10. The spring 13 is fitted onto a center part of the stopper portion 11.
In a normal condition in which no impact force is applied to the vehicle, the weight portion 10 is biased rearward of the vehicle body by the spring 12, and thus a swelling portion 10a formed on the upper side of a rear end part of the weight portion 10 is located behind a lower end part of the stopper portion 11. In addition, since the stopper portion 11 is biased upward by the spring 13 using a collar portion 11a, the lower end part of the stopper portion 11 is located above the swelling portion 10a of the weight portion 10.
In this state, an upper end part of the stopper portion 11 penetrates a hole provided in the attachment flange 6, and thus protrudes upward. When the lid 4 is closed, the upper end part of the stopper portion 11 is in contact with the rear side of the lid 4.
In this case, since there is a space S between the lower end part of the stopper portion 11 and the weight portion 10, the stopper portion 11 and the weight portion 10 do not interfere with each other even if the lid 4 is pushed. Thus, the lid 4 can be pushed.
Consequently, as shown in FIG. 2A, it is possible to lift down the engagement pin portions 5 in the direction indicated by an arrow in the drawing by pushing the closed lid 4. Each time the lid 4 is pushed, the state of holding the engagement pin portions 5 and the state of releasing the engagement pin portions 5 are alternately changed repeatedly. Correspondingly, the locked state of the lid 4 and the unlocked state of the lid 4 are switched back and forth.
Meanwhile, in a case where impact force acts on the vehicle from the front of the vehicle body due to a vehicle collision or the like while the lid 4 is locked by the lock devices 7, inertial force acts on the lid 4 toward the front of the vehicle body, and thus the lid 4 moves toward the front of the vehicle body as shown in FIG. 2B, as in the case where the lower part of the lid 4 is pushed.
In this event, since the inertial force simultaneously acts on the weight portion 10 and the lid 4, the weight portion 10 slidingly advances toward the front of the vehicle body, and thus the swelling portion 10a moves to a position below the stopper portion 11. For this reason, the lower end part of the stopper portion 11 hits an upper surface of the swelling portion 10a. 
Thereby, the descending movement of the stopper portion 11 is blocked, which in turn blocks the descending movement of each engagement pin portion 5, and prevents the lock devices 7 from releasing the engagement pin portions 5 from their lock states. Consequently, even if the impact force acts on the vehicle from the front of the vehicle body due to the vehicle collision or the like, the lid 4 does not open.
Meanwhile, when impact force acts on a vehicle due to a vehicle collision or the like, acceleration occurs in every object inside the vehicle along with input of this impact force into the vehicle. This acceleration varies depending on factors such as an amount of impact force produced at a time of collision, and colliding manner.
In the conventional lid lock structure of a storing box for a vehicle, the weight portion 10 and the spring 12 are connected together. Thus, the sliding movement of the weight portion 10 due to inertial force produced at the time of the collision is damped by elastic force of the spring 12.
In such conventional structure, the weight portion 10 has a peculiar movement characteristic determined by the mass of the weight portion 10 and the strength of the spring 12. For this reason, the weight portion 10 starts its sliding movement in sensitive response to a particular level of acceleration produced at the time of a collision, but is less likely to show a response to a different level of acceleration. Thus, with some level of impact force and some way of collision, the weight portion 10 may not slide to such a location that the stopper portion 11 is prevented from moving downward.
If the weight portion 10 does not slide to such a location that the descending movement of the stopper portion 11 is prevented as described above, it is likely that: the stopper portion 11 descends; in response to this, the engagement pin portions 5 descend; the lock devices 7 release the lock; and consequently, the lid 4 opens.
Furthermore, in the conventional structure, it is difficult to set conditions for the operation of the restriction device 8. That is because consideration needs to be given to the movement characteristic peculiar to each of the weight portion 10 and the spring 12 when the operation conditions of the restriction device 8 are set.
Moreover, in the conventional structure, even if the operation conditions of the restriction device 8 are changed by changing the mass of the weight portion 10 and the strength of the spring 12, nothing but the level of acceleration to which the weight portion 10 sensitively responds is changed. This brings about a problem that the weight portion 10 still sensitively responds to a particular level of acceleration, whereas the weight portion 10 is hard to respond to a different level of acceleration, and thereby the restriction device 8 does not operate in some cases depending on impact force and how the vehicle collides.
Against this background, an object of the present invention is to provide a lid lock structure of a storing box for a vehicle which allows operation conditions to be set easily, and which is capable of securely locking the lid of the storing box, when the vehicle receives impact force due to a vehicle collision or the like, regardless of a level of acceleration produced at a time of the vehicle collision.